Let the width be x, the length be (28/ 15)X, the area be 420m2 = (28/ 15) x and x= 15, then the width be 15 m and the length be 28m.

Because there is an open space of 1 m around, it is (28+ 1) long and (15+ 1) wide, 29×16 = 464m2. The answer is that a basketball court can be built on this open space.